A Direct Molding Technique to Fabricate Silica Micro-Optical Components

摘要

A technology for the direct molding and release of silica micro-optical components in polymethyl methacrylate (PMMA) molds is developed. The objectives of this work are to by-pass some of the usual steps in deep x-ray lithography (DXRL) and to determine the suitability of GR650 resin (methylpolysilsequioxane) for molding thick, high aspect ratio structures. The process is initiated by DXRL exposure of PMMA, followed by spin-on glass application, a cure at 85 deg C to set the shape of the resin, followed by demolding. The cure is below the glass transition temperature of PMMA and the demolding process allows re-use of the mold. There is no need for electroforming in the replication process. PMMA molds with thickness of 250, 350 and 500 um were fabricated by EXRL and standard resist development. A novel metal sacrificial layer technique is used in the release process with initial yield of about 50